Drilling apparatus locking assembly



March 12, 1968 Filed April 26, 1965 R. H. CULLEN ET L DRILLING APPARATUS LOCKING ASSEMBLY 4 Sheets-Sheet 2 (bar/e: H. ///0f2 wmm/e A/rer 4 INVENTORS 7 J ll-04L ATTO/PNE VJ March 12, 1968' DRILLING APPARATUS LOCKING ASSEMBLY Filed April 26, 1965 I 1 l I H. CULLEN ET AL 3,372,762

4 Sheets-Sheet 3 March 12, 1968 R CULLEN ET AL 3,372,762

DRILLING APPARATUS LOCKING ASSEMBLY Filed April 26, 1965 4 Sheets-Sheet 4 5 4/7/27/77/9 Aker INVENTORS lay 64 1.... Z

ATTORNE'YJ United States Patent DRILLING APPARATUS LOCKING ASSEMBLY Roy H. Cullen, Charles H. Elliott, and Jimmie R. Aker,

Houston, Tex., assignors, by direct and mesne assignments, to The Youngstown Sheet and Tube Company,

a corporation of Ohio 7 Filed Apr. 26, 1965, Ser. No. 450,889 8 Claims. (Cl. 175-104) ABSTRACT OF THE DISCLOSURE Drilling apparatus wherein a housing having a plurality of rotatably releasable housing sections is surrounded by a locking sleeve having means for locking to the upper and lower ends of the housing to thereby prevent relative rotation and inadvertent release of the housing sections. In one form, the apparatus has means for placing the outer sleeve under compression and the housing under tension.

As shown in United States Patent No. 3,136,113, flexible driling hose has now been developed for use in commercially drilling wells to depths which are comparable to, and even greater than, the depths being drilled using standard drill pipe to support the drill bit. The present invention relates to the use of such a flexible drilling hose together with an electric cable extending therethrough for operating an electric motor to drive a drill bit while drilling mud is supplied to the hit through the hose.

It is therefore an object of the present invention to provide a new and improved downhole drilling apparatus wherein an electric motor apparatus is supported in a well on a flexible drilling hose for driving a drill bit, and wherein power is supplied to the motor through an electric cable extending through the flexible drilling hose while drilling mud is supplied through the hose to the bit for drilling operations.

Another important object of this invention is to pro- 'vide a new and improved downhole drilling apparatus which includes a power assembly having a plurality of sections threaded together, and which also includes tubular means for locking such threads to prevent their inadvertent release.

A further object of this invention is to provide a new and improved downhole drilling apparatus wherein an electric motor and related parts for driving an electric motor are threadedly connected together, and wherein a tubular sleeve is connected externally of the motor and its related parts for locking the threaded connections, such sleeve also having means therewith for bypassing drill- I ing fluid around the motor and its related parts.

Still another important object of this invention is to 3 provide a new and improved downhole drilling apparatus which includes a power assembly having a plurality of sections threaded together, and which also includes wherein power is supplied to the motor through an electric, cable extending through the flexible drilling hose while drilling mud is supplied through the hose to the bit for drilling operations, and wherein means are provided for bypassing the drilling mud around the electric motor 3,3 72,762. Patented Mar. 12, 1968 so that the mud flows from the hose to the bit without contacting the motor. 2

The preferred embodiment of this invention will be de scribed hereinafter, together with other features thereof, and additional objects will become evident from such description. I

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIG. 1 is a schematic view illustrating the downhole drilling apparatus of this invention;

FIGS. 2A, 2B, 2C, 2D, 2E and 2F, illustrate the down hole drilling apparatus of this invention in detail;

FIG. 3 is a cross-sectional view taken on line 33 of FIG. 2A;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 2A; and

FIG. 5 is a cross-sectional view taken on line 55 of FIG. 2F.

In the drawings, the letter B designates a conventional drill bit which is adapted to be positioned in a bore of a well for drilling purposes. The drill bit B is driven by an electric motor disposed within a motor housing H, as will be more fully explained hereinafter. The housing H and the parts connected therewith are supported in the well by a drill stern D which is preferably a flexible drilling hose of the type referred to in United States Patent 3,136,113. Suitable drill collars C may be provided in the drill string D for additional weight, if desired. As will be explained more in detail, a locking sleeve L is locked to the housing H to place the housing H under a prestress and to also lock the relatively rotatable sections of the housing H together to prevent an inadvertent rotation of such sections relative to each other. It is also important to note that the electrical power for operating the motor within the housing H is supplied through the flexible drilling hose or stem D by means of an electrical cable E which extends throughout the length of such drilling hose or string D. Thus, with the present construction, electrical power is supplied to the motor for operating the drill bit B, and drilling mud is supplied through the drilling hose D to the bit B while bypassing the mud around the housing H to prevent contact of the drilling mud or fluid with the motor and other parts in the housing H.

Considering the invention more in detail, the housing H as referred to herein extends from an upper section 10 (FIG. 2A) to a lower section 12 (FIG. 2F). Between the upper section 10 and the lower section 12 of the housing H is a plurality of sections which are numbered consecutively as sections 14, 15, 16, 17, 18, 19, 20 and 21, all of which are rotatably releasable with respect to each other since they have threaded connections between adjacent sections.

The housing H is adapted to receive and hold a plurality of units or parts, the number and construction of which may be varied within the scope of this invention. For example, an electric motor 25 is disposed within the housing H (FIG. 2B), such motor 25 being of any conventional construction suitable for positioning in the downhole drilling apparatus of this invention and which is adapted to be supplied with electrical power through the cable E extending from the surface of the well (FIG. 1). The details of the motor 25 are not important insofar as this invention is concerned and therefore are not illustrated, but it can be seen in FIG. 2B that the electric wires 26 from the electric cable E (FIG. 1) are interconnected through an electrical plug 27 with the coils of the motor 25 in any known manner so as to operate the motor drive shaft 28. The motor drive shaft 28 is preferably disposed in an upward thr-ust bearing 36 (FIG. 2B) and extends downwardly through the motor to a slip clutch 32 (FIG. 20). A typical slip clutch which may be used at 32 is illustrated in our copending application Ser. No. 323,024 filed in the United States Patent Oflice on Nov. 12, 1963, now United States Patent No. 3,232,362 issued Feb. 1, 1966.

A shaft from the slip clutch 32 passes through suitable support bearings 33 and 34 (FIG. 2C) and is operably connected to a suitable gear box .15 for gear reduction. A hearing 36 is disposed below the gear box and a second bearing 37 is also provided. The shaft extending downwardly from the bearing 37 is joined to another shaft section by a shaft connector 38 which then passes through an oil seal 39. Below'the oil seal 39, an oil protector section 49 which may be of conventional con struction, is disposed for separating the oil which is pro- 'vided within the housing H from mud used in drilling, as Will be more evident hereinafter. A shaft bearing 43. is disposed below the oil protector section 40 (FIG. 2D), and another bearing 42' is disposed below the bearing section 41.

A second oil seal 43 is provided below the bearing 42 (FIG. 2E), and an oil-mud equalizer 44 having a flexible external sleeve 44a is provided below the seal 43 and extending down to the lower main seal 45 which keeps the drilling mud from entering the oil in the housing H.

Although the various components that are preferably utilized within the housing H in the preferred form of this invention have been illustrated in the drawings, it will be appreciated that such parts are basically provided to connect the motor 25 to an operating bit shaft which serves to rotate the drill bit B. It is desirable to also provide a shock-absorber 49 between the seal 45 and the bit shaft 56 (FIG. 2F), as more fully described -in said copending application Ser. No. 323,024. As seen in FIG. 2F, the bit shaft 50 is provided with a threaded tool joint 51 to which the drill bit B (FIG. 1) or any other suitable tools such as core barrels, drill collars, and shock subs, or any combination thereof, may be connected for use.

With respect to this invention, it is significant that the housing H is sealed off at its upper end by a packing which is retained in sealing position by a packing gland 52 (FIG. 2A) near the upper end of the housing H. Also, the seal 45 (FIG. 2F) at the lower end of the housing H seals off the housing to retain oil within the housing H and to prevent drilling mud or fluid from mingling with the oil within the housing H.

As best seen in FIGS. 2A and 3, the electrical cable E extends through the packing gland '52, and a seal is :provided around such electrical cable E to prevent any flow of drilling mud into the housing H below the packing gland and seal therewith.

The electrical cable E is shown with an electrical plug or connector 53 which connects with another length of cable E thereabove, or which extends to the surface of upper end of the housing H, preferably with drill collars C interposed therebetween so that the drill string D supports or suspends the housing H and the drill bit B there- -'below. As seen in FIG. 2A, the upper section 10 of the housing has a tool joint adapter 55 connected thereto which has internal threads 55a of conventional construction for connection to a suitable drill collar such as indicated schematical at C in FIG. 1. The flexible drill stem or hose D is then connected above the drill collar C so that drilling mud or fluid for drilling purposes may be passed downwardly through the flexible hose D and the the well for connection to a source of electrical power drill collars C into the bore 10:: of the upper section 10 of the housing H. The packing provided with the packing gland 52 prevents the drilling mud from entering the upper end of the housing H except to the extent that it enters the bore 10a. Suitable openings 1012 are provided (FIGS. 2A and 4) through which the drilling mud is bypassed to a point externally of the housing H and internally of the locking sleeve L, as will be more evident hereinafter. The drilling mud is returned from the sleeve L for flow to the drill bit B through return ports 12a provided in the lower housing section 12 (FIGS. 1 and 2F). The drilling mud or fluid thus bypasses the housing H so as to bypass the motor 25 and the related parts carried within the housing H to prevent an intermingling of the drilling fluid with the oil surrounding the motor 25 and the other parts within the housing H. l

The locking sleeve L not only provides the longitudinal passage 56 (FIG. 1) externally of the housing H for the bypassing of the drilling mud or fluid, but it also serves to lock the threaded sections of the housing H to prevent an inadvertent or premature release thereof.

The lower end of the sleeve L has a locking element 60 welded, integral, or otherwise formed with the sleeve L and which has one or more locking lugs 60a therewith (FIGS. 2F and 5). Such lugs Mia extend into recesses 1212 which are formed in the external surface of the lower housing section 12 or some part which may be connected thereto. The interfitting of the lugs 60a in the grooves 12b prevents relative rotation between the sleeve L and the lower housing section 12. A

At the upper end of the sleeve L a locking element 62 is welded or otherwise secured having a keyway 62a formed therein for receiving a key 63 positioned in a suitable slot 10c of the upper housing section 10. Suitable mating splines may be provided in lieu of the key 63 and keyway 6211. Such key 63 in the keyway 62a, of the suitable mating splines, serve to prevent relative rotation between the housing section 10 and the sleeve L while permitting rela= tive longitudinal movement therebetween. To facilitate as sembly in manufacture, the locking element 62 is pref erably formed in two sections with the lower section 625 being welded directly to the sleeve Land with serrations 62c on the upperand lower interengaging edges of the two portions of the elements 62 to prevent relative ro ta= tion therebetween (FIGS. 2A and 3). The lower section 62b thus may omit the groove 62a so as to provide a smooth annular surface with which to engage a seal 6. a An annular nut 65 is threaded on the externalsurface of the upper housing section 10 so that upon rotation thereof relative to the upper housing section 10, the sleeve L may be placed under compression and at the same time the entire housing H may be prestressed. The extent of such compression of the sleeve L and the prestress of the hous ing H will depend upon the anticipated weight to be 1m posed on the housing H during the drilling operations The prestress imparted to the housing H under ideal conditions would be suflicient to counteract the weight which would be placed upon the housing H by the drill collars C and other weight thereabove in use. In any event, the extent of the prestress of the housing H should be suflicient to at least partially compensate for the weight imposed on the housing H during drilling operations. Preferably, the housing H will be in a neutral stress or ano-stress condition when the weight ofthe drill collars C and the parts thereabove are imposed on the housing H in use due to the prestress placed in the housing H with the nut 65, as previously explained. Thus, the locking sleeve L may serve three purposes in the present invention, namely: (1) for bypass ing the drilling mud around the housing H to prevent a contact of the drilling mud or other fluid with the motor '25 and any parts which should be isolated from the mud, (2) for preventing an inadvertent release of the housing sections when the housing H is made up of a plurality of rotatably releasable sections as in the preferred embodiment disclosed herein, and (3) for prestressing the housing H to at least partially compensate for the weight or load imposed thereon in drilling operations.

The sleeve L may also be connected with the housing H so that the sleeve L has imparted thereto pulling or tension forces which may be exerted on the housing H when pulling upwardly on the pipe D to thereby reduce or substantially eliminate any pulling or tension forces on the motor 25. For example, the lower end of the locking sleeve L may be secured to the lower housing section 12 by a collar 75 which has an inner lower shoulder 75a engageable with an external housing shoulder 120 when threads 75b and 6011 are threaded together (FIG. 2F). The upper end of the sleeve L may have a threaded tension ring 80 threaded at 80a in the bore of the section 62b so that upward pulling forces on the housing H are transmitted from a shoulder d to a shoulder 80a on the ring 80, and thus to the sleeve L. Thus, should the bit B or other tool become stuck in the well, any tension or pulling force exerted an the pipe P is transmitted to the sleeve L to avoid applying dangerous tension or pulling forces to the motor 25.

In the operation or use of the downhole drilling apparatus of this invention, the apparatus is generally assembled as schematically illustrated in FIG. 1 so as to be supported from the surface of the well with the flexible drilling hose or drill pipe D and with electrical cable E extending therethrou'gh from the surface to the electrical motor 25 within the housing H. The drill bit B is placed on the bottom of the well bore being drilled and then electrical power is supplied to the motor 25 for driving the various shafts and parts connected below the motor 25 'and ultimately connected to the drill bit B. During such drilling with the bit B, drilling mud is circulated downwardly through the drilling hose or stem -D and is bypassed through the ports 1012, the annular space 56 with the locking sleeve L and then is returned through the ports 12a to flow downwardly into the drill bit B for discharge therefrom in the usual manner. The housing H is preferably prestressed as explained heretofore so that at least a part of the weight imposed thereon is compensated for by the prestress of the housing H. Since the upper section 10 and the lower section 12 of the housing H are locked to the locking sleeve L, all of the sections of the housing H therebetween are also locked to prevent relative rotation thereof. This is extremely important particularly in drilling operations where vibrations necessarily occur. Should the threaded connections between the various housin'gsections become inadvertently rotated relative to each other, leakage of drilling mud into the oil system surrounding the motor 25 could occur which would be damaging, particularly if the drilling mud or fluid in the well is abrasive in nature. This invention thus not only reduces the danger of leakage, but it also eliminates the greater danger of a complete release of one or more of the housing sections from its adjacent section.

Although the invention has been described herein in connection with a housing H which is made up of a plurality of sections which are threaded together, it will be understood from the previous description that the housing H may be formed of a single piece, from he prestressing thereof may still be of significant value to compensate at least in part for the weight or load The foregoing disclosure and description of the invention are illustrative and explanatory thereof; and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) threaded connection means for connecting the adjacent sections,

(c) an external sleeve disposed over said housing,

((1) means locking said sleeve to the upper and lower sections of said housing to prevent relative rotation of the sections of the housing, and i (e) said sleeve being spaced from said housing to provide a longitudinal flow passage in the sleeve externally of the housing to bypass fluid around the housing.

2. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) threaded connection means for connecting the adjacent sections,

(c) an external sleeve disposed over said housing,

(d) means locking said sleeve to the upper and lower sections of said housing to prevent relative rotation of the sections of the housing, and

(e) means for placing said sleeve under compression and said sections of the housing under pre-stress to at least partially compensate for weight imposed on the housing in use.

3. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) threaded connection means for connecting the adjacent sections,

(c) an external sleeve disposed over said housing,

(d) a lower lock means locking the lower end of said sleeve to the lower section of the housing to prevent relative rotation and longitudinal movement therebetween,

. (e) an upper lock means locking the upper end of said sleeve to the upper section of the housing to prevent relative rotation while permitting longitudinal movement therebetween, and

(f) means on the upper section of the housing and engageable with the upper end of the sleeve for pre-stressing the housing.

4. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) threaded connection means for connecting the adjacent sections,

(c) an external sleeve disposed over said housing,

(d) a lower lock means locking the lower end of said sleeve to the lower section of the housing to prevent relative rotation and longitudinal movement therebetween,

(e) an upper lock means locking the upper end of said sleeve to the upper section of the housing to prevent relative rotation while permitting longitudinal movement therebetween, and

(f) an adjustable nut threaded on the upper section of the housing and engageable with the upper end of the sleeve for imparting relative movement between the sleeve and the housing to place the sleeve under compression and the housing under a prestress.

5. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) rotatably releasable connection means for connecting the adjacent sections,

(0) an external sleeve disposed over said housing,

(d) means locking said sleeve to the upper and lower sections of said housing to prevent relative rotation of the sections of the housing, and

(e) said sleeve being spaced from said housing to provide a longitudinal flow passage in the sleeve externally of the housing to bypass fluid around the housing.

6. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(b) rotatably releasable connection means for connecting the adjacent sections,

(0) an external sleeve concentrically disposed over said housing to provide an annular space between the housing and the sleeve for the passage of fluid externally of the housing through the sleeve,

(d) means locking said sleeve to the upper and lower sections of said housing to prevent relative rotation of the sections of the housing, and

(e) said sleeve being spaced from said housing to provide a longitudinal flow passage in the sleeve externally of the housing to by-pass fluid around the housing.

7. Drilling apparatus, comprising:

(a) a downhole electric motor adapted to be positioned in a well bore,

(b) a flexible drilling hose,

(0) means connecting said electric motor to and below said drilling hose,

(d) an electric cable extending through the bore of the drilling hose,

(e) means electrically connecting said cable to said motor,

(f) means for sealing off said motor from drilling fluid,

(g) a housing formed of a plurality of rotatably releasable sections surrounding said motor,

(h) a locking sleeve locked to the upper and lower sections of the housing to prevent inadvertent release of the sections thereof, and

(i) means for by-passing fluid through the sleeve and around the housing.

8. Drilling apparatus, comprising:

(a) a housing adapted to be disposed in a well and having a plurality of sections,

(-b) threaded connection means for connecting the adjacent sections,

(c) an external sleeve disposed over said housing,

(d) a lower lock means locking the lower end of said sleeve to the lower section of the housing to prevent relative rotation and longitudinal movement therebetween,

(e) an upper lock means locking the upper end of said sleeve to the upper section of the housing to prevent relative rotation while permitting longitudinal movement therebetween,

(f) means on the upper section of the housing and engageable with the upper end of the sleeve for prestressing the housing,

(g) means at the lower end of said sleeve for transmitting upward tension forces in the sleeve to the lower end of the housing, and

(h) means at the upper end of said sleeve for transmitting upward tension forces on said housing to said sleeve whereby upward tension forces on the housing are carried by the sleeve.

References Cited UNITED STATES PATENTS 1,307,847 6/1919 Bray 175-25 2,355,342 8/1944 Van Wormer 175-104 X 2,609,182 9/1952 Arutunoff 175-104 X 2,868,507 1/1959 Scott et al 175-105 X 3,011,844 12/1961 Maha et al 52--223 X 3,232,638 2/1966 Hollander 175-3.20 X 2,927,806 3/1960 Lahee 285-115 ERNEST R. PURSER, Primary Examiner. 

